Aircraft



FIG. 1 is a right side elevation view of an aircraft showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevation thereof;

FIG. 4 is a rear elevation view thereof;

FIG. 5 is a bottom plan view thereof; and

FIG. 6 is a left side elevation thereof. 

The ornamental design for an aircraft, as shown and described. 